DESCRIPTION: Deficits in speech-understanding ability are common among individuals over 65 years of age. This seems to be particularly true for speech degraded by background noise and reverberation. In a series of experiments conducted during the first five years of this project, it has been found repeatedly that the primary component contributing to individual differences in speech understanding has been the degree of hearing loss. This has held true for simple speech materials, such as nonsense syllables, and more complex materials, such as high-context sentences, when presented in quiet and in noise at a wide range of sound levels (up to 90 dB SPL). Given the primary importance of audibility in the explanation of the speech-understanding problems of the elderly, one would expect that the conventional hearing aid would provide considerable benefit to this population. Unfortunately, this does not appear to be the case. Individuals over the age of 65 represent the largest group of hearing-aid purchases in the U.S. and the general satisfaction with hearing aids by their purchasers is quite low. It is the general aim of the proposed project to improve the success afforded to the elderly by conventional hearing aids. This general aim will be accomplished through determination of the individual factors associated with successful hearing-aid use in the elderly in a prospective clinical study of 432 elderly hearing-aid users followed over a five-year period.